JP2007288312A - Data collection method and data collection system using wireless lan - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a data collection system, provided with many wireless terminals and capable of receiving data whose size is not large from the many wireless terminals in a short time, by using a wireless LAN system wherein the problem of difficulty in quickly receiving data from the many terminals in a short time is solved. <P>SOLUTION: In the data collection system, using the wireless LAN provided with a data collection apparatus, access points and many wireless terminals, the data collection apparatus communicates with the wireless terminals by broadcasting via the access points, the wireless terminal for transmitting data are selected by the access points, and the wireless terminals transmit the data, after receiving an instruction. Collision of data signals on the data transmission can be avoided, by controlling the transmission of the wireless terminals by the access points, in this way. As a result, the communication time of data transmission can be reduced significantly. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a data collection method and a data collection system using a wireless LAN, and in particular, even when the number of wireless terminals that transmit data increases, the response results are immediately received, aggregated, and the results are disclosed in real time. The present invention relates to a data collection method and a data collection system using a wireless LAN that can be used.

  At various meetings, the moderator asks the participant a question, the participant answers the question, and the response results are immediately aggregated to recognize the usefulness of the data collection system disclosed to the participant. Such a system has come to be used in many gatherings as a questionnaire system or a response system. The real-time data collection system has a major feature in that it can not only ask participants to reply to inquiries, for example, at meetings, but also collect the results of responses to inquiries from participants and immediately disclose them to the participants. is there. Here, in order for the data collection system to be a real-time type, it is desirable that the waiting time until the result of receiving and summing up the responses to the inquiry items is disclosed is within 1 second, and within 2 seconds at the longest. Is required. The configuration of such a data collection system requires a data collection system that can collect data within such a time.

  In a real-time data collection system, responses from respondents to a question are transmitted almost simultaneously from a plurality of wireless terminals. Therefore, when the number of wireless terminal devices increases, there are many data collection devices that receive response data. Will be sent concentrated within a short time. Therefore, a data collection device that receives a response is required to be able to receive such a large amount of response data quickly.

  As a real-time data collection system, in addition to a device using a wire as described in Patent Document 1, for example, a wireless device that does not require wiring, for example, a wireless radio wave as described in Patent Document 2 is used. In addition, devices using infrared light as described in the cited document 3 have been developed.

  By the way, wireless systems such as mobile phones have been remarkably developed in recent years, and their use has been standardized and standardized. Therefore, if a real-time response data collection system can be configured based on such a standardized wireless system, advanced wireless system technology can be used easily, and standardized components can be used and maintained. The real-time data collection system is expected to be further developed.

  However, if the mobile phone system, which is the most widely used wireless system, is used to specifically configure the data collection system, there is a real difficulty in making it real-time. Recognize. In the cellular phone system, since it is not originally assumed that data from a large number of terminals (for example, 500 or more wireless terminals) is received in a short time, a large number of responses are quickly received by the cellular phone system. Is very poor.

  There is a wireless LAN system as another wireless communication system that has been widely standardized and standardized. The wireless LAN system is being standardized as IEEE 802.11 (Non-Patent Document 1). A similar wireless LAN system can be configured based on a standard such as ETS 300 328 (Non-Patent Document 2).

Wireless LAN systems standardized as IEEE 802.11 include 11b, 11a, and 11g, and have the following characteristics.
(1) An infrastructure mode composed of a base station and a terminal and an ad hoc mode in which the terminals directly communicate with each other are defined. In the infrastructure mode, it can be combined with another LAN.
(2) Multiple terminals or base stations share a space as a communication medium, and when a certain terminal or base station is transmitting radio waves, other terminals or base stations do not emit radio waves (Carrier Sense) (Multiple Access with Collation Avidance, CSMA / CA).
(3) As a method for managing transmission of radio waves from a terminal or a base station, a DCF (Distributed Coordination Function) method is usually used, and a PCF (Point Coordination Function) method is prepared as an option. In DCF, multiple access is performed in a distributed manner by CSMA / CA and virtual carrier sense that avoids the hidden terminal problem. On the other hand, in the PCF, a central station for assigning channels is introduced, and a terminal having transmission data sends a request for transmission permission to the central station, and when the permission (polling) from the central station is made, the data is transferred. Send.

  In a real-time data collection system, data of responses to inquiries is transmitted almost simultaneously from many wireless terminals (for example, 500 or more wireless terminals). Although the size of the response data is not large, the data collection device is required to promptly receive and aggregate many response data concentrated in a short time and disclose the results. However, in a normal wireless LAN system, it is not assumed that a very large amount of response data that is transmitted in a concentrated manner within a short time is received promptly. For this reason, when the amount of response data transmitted increases, in normal operation, collision between response data increases, communication time is wasted, and throughput is drastically reduced. Pages 121-126 of Non-Patent Document 3 describe throughput evaluation in DCF of IEEE 802.11 wireless LAN. By increasing the amount of transmission traffic, the throughput reaches saturation relatively easily. It has been shown that the throughput does not increase even if the amount is further increased, and in some cases, it decreases.

  In addition, the response of PCF (Point Coordination Function) prepared as an option in IEEE 802.11 is performed, and response data is received by polling many wireless terminals one after another. There are ways to avoid collisions between data. However, for example, in a data collection system having 500 or more wireless terminals required in many meetings, even if such a PCF operation is used, much time is still required for transmission and reception only by performing a normal PCF operation. Therefore, a real-time data collection system could not be realized only by using the PCF operation.

As described above, when an existing wireless LAN system is normally used, data cannot be collected and collected in real time from a large number of wireless terminals.
JP 10-320604 A JP 04-296990 A WO2001 / 073630 ANSI / IEEE Standard 802.11 European Telecommunication Standard ETS 300 328 Komaki Sangoku Wireless LAN and Ubiquitous Network (Wireless Technology and its Applications 3) Maruzen Co., Ltd. (2004)

  The present invention has a problem with the above-described existing wireless LAN system, that is, it is difficult to quickly receive a large amount of response data transmitted from many terminals concentrated in time. Solved, especially when the size of individual response data sent from a large number of wireless terminals within a short time is not very large, but when the number of response data is large, these response data are quickly received and aggregated The present invention provides a data collection method using a wireless LAN system capable of disclosing the results in real time, and a data collection system using the wireless LAN system.

  The data collection method of the present invention includes a plurality of wireless terminals that transmit data such as response data, an access point that is wirelessly connected to the plurality of wireless terminals and receives data transmitted from the plurality of wireless terminals, and a plurality of wireless terminals And a data collection method using a wireless LAN for collecting data transmitted from a plurality of wireless terminals by the data collection device, the data collection method comprising: A signal for establishing a communication channel is transmitted from a point to a plurality of wireless terminals to establish a communication channel, and the correspondence information between the IP address and MAC address of the data collection device is transmitted from the access point to the plurality of wireless terminals. Then, specify a specific wireless terminal from among multiple wireless terminals from the access point to multiple wireless terminals. Was a data transmission instruction transmitted to a specific wireless terminal by broadcast, and each of the plurality of wireless terminals was designated in response to the data transmission instruction transmitted by broadcast from the access point? It is characterized in that data is transmitted when it is determined whether or not it is designated.

  In this way, a specific wireless terminal that transmits data within a certain communication period is designated, and only a limited number of designated wireless terminals transmit data, thereby preventing collisions between response signals during transmission. The loss of communication time due to collision is eliminated. Designation of a specific wireless terminal to transmit data at this time may be performed by grouping the wireless terminals, dividing the communication period according to the group, and sequentially designating each group in different communication periods. By doing so, it has been found that the communication time can be greatly reduced as compared with the case where the wireless terminal transmits the response data without specifying the grouping of the wireless terminals or dividing the communication period.

  For the designation of the wireless terminal, a plurality of wireless terminals can be grouped within a predetermined communication period range, specified together for each group, and the transmission of a response signal can be commanded within the predetermined communication period. In this case, the number of wireless terminals specified within a predetermined communication period may be set to a number that does not cause a problem of collision between signals at the time of transmission in consideration of the size of response data. By sequentially designating such wireless terminals that transmit data, it is possible to request data transmission to all of the plurality of wireless terminals.

  Instead of individually transmitting a specific wireless terminal from the access point and a data transmission instruction to the specified wireless terminal to a plurality of wireless terminals, each wireless terminal transmits this collectively by broadcasting. The time required for communication as a whole system can be greatly shortened by a method of determining whether or not a transmission instruction target is designated from a transmission instruction transmitted by broadcasting.

  It is desirable that the broadcast transmission regarding the designation of the wireless terminal from the access point and the data transmission instruction to the designated wireless terminal is repeatedly performed every predetermined time.

  The data transmission instruction to the designated wireless terminal preferably includes transmission timing designation for designating a data transmission time range from the wireless terminal. In addition, it is desirable that the designated wireless terminal transmits data within the designated time range and asynchronously with other designated wireless terminals. Asynchronous here means that each specified wireless terminal performs carrier sensing for a random time called back-off, and data is transmitted sequentially from terminals that have confirmed that other terminals are not transmitting. Is Rukoto.

  Each of the plurality of wireless terminals is assigned identification information for identifying the individual wireless terminal, and the response signal transmitted from each of the plurality of data collection devices identifies the individual wireless terminal. It is desirable to include identification information. By doing so, it is possible to determine which wireless terminal is the response data from each wireless terminal and process the data for each response data that arrives at the access point from the wireless terminal.

  In addition, the access point broadcasts a response signal that reports that data has been received from these wireless terminals after a predetermined time has elapsed since the data was received from these specific wireless terminals. be able to.

  In this way, the response signal for data reception from the wireless terminal is not transmitted every time it is received, but is transmitted in a lump by broadcast, thereby greatly reducing the time required for communication as a whole system. I was able to.

  The response signal transmitted from the access point includes a field including predetermined bits for individually specifying the plurality of wireless terminals, and the plurality of wireless terminals are individually associated with the bit positions of the field. Can be like that.

  By doing so, the response signal for data reception from the access point by broadcasting has become clear, and for example, it is very easy to detect the presence / absence of a response signal for data transmission in each wireless terminal.

  Further, response signals for the reception of data transmitted from each of the plurality of wireless terminals are collected from the access point and broadcast at regular intervals, and each wireless terminal performs broadcast transmission from the access point. If the response signal for the data transmitted by the wireless terminal is not included, the data can be retransmitted.

  Further, the data collection method using the wireless LAN of the present invention may cause the wireless LAN to perform a PCF operation. That is, a plurality of wireless terminals that transmit data, an access point that is wirelessly connected to the plurality of wireless terminals and that receives data transmitted from the plurality of wireless terminals, and the access point that is transmitted by the plurality of wireless terminals A data collection method for collecting data transmitted from the plurality of wireless terminals by the data collection device using a data collection device for collecting received data, the access point to the plurality of wireless terminals A communication channel is established by transmitting a signal for establishing a communication channel, and the access point acquires information indicating operating states of the plurality of wireless terminals after the communication channel is established, The correspondence information between the IP address and the MAC address of the data collection device is transmitted to The access point instructs data transmission to a predetermined wireless terminal corresponding to the information indicating the operating state in the plurality of wireless terminals based on the data transmission instruction from the data collection device, and the data from the access point The wireless terminal may transmit data in response to the transmission instruction.

  In this way, it is possible to specify one by one for a plurality of wireless terminals and transmit data, and there is no possibility of collision of data transmission signals, so the communication time of the entire system can be reduced. Can be shortened. In the case of causing the system to operate the PCF, it has been found that, as in the case of the DCF operation, the use of broadcast for communication from the access point to the wireless terminal can significantly reduce the communication time.

  Next, a data collection system using a wireless LAN according to the present invention includes a plurality of wireless terminals, an access point that is wirelessly connected to the plurality of wireless terminals and receives data transmitted from the plurality of wireless terminals, and an access point. Data using a wireless LAN that includes a data collection device that collects and aggregates data received from a plurality of wireless terminals and a disclosure device that discloses the aggregation results of the data collection device, and immediately discloses the aggregation results of the data collection device A collection system, wherein a plurality of wireless terminals each receive a signal for establishing a communication channel issued by an access point to the plurality of wireless terminals and establish a communication channel, and a plurality of access points That receives correspondence information between the IP address and MAC address of the data collection device -Less receiving means, a plurality of wireless terminals are grouped into a plurality of groups, each group is sequentially designated, and broadcast from an access point that instructs the wireless terminals belonging to the designated group to transmit data Response determining means for receiving transmission and determining whether or not to respond in response to a data transmission instruction transmitted by broadcast, and transmitting data to be transmitted when it is determined that a response should be obtained A response transmission unit, and the access point transmits a signal for establishing a communication channel to a plurality of wireless terminals to establish a communication channel, and the IP of the data collection device to the plurality of wireless terminals. Address correspondence transmission means for transmitting correspondence information between an address and a MAC address, and the plurality of wireless terminals according to a command from the data collection device A data collection apparatus having data transmission instruction broadcast means for dividing a plurality of groups, sequentially designating each group, and transmitting a response data transmission instruction to a wireless terminal belonging to the designated group by broadcast Divides a plurality of wireless terminals into a plurality of groups, sequentially designates each group that has been grouped, and transmits an instruction to transmit data to the wireless terminals belonging to the designated group by broadcast to the access point And a data transmission instruction broadcast command means.

  This data collection system using a wireless LAN of the present invention is a data collection system suitable for implementing the above-described data collection method of the present invention.

  Further, the data collection system using the wireless LAN of the present invention may perform a PCF operation. That is, a data collection system using a wireless LAN according to the present invention is acquired by a plurality of wireless terminals, an access point that is wirelessly connected to the plurality of wireless terminals and receives data transmitted from the plurality of wireless terminals, and the access point. A data collection device that collects and aggregates data transmitted from a plurality of wireless terminals and a disclosure device that discloses the aggregation results of the data collection device, and uses wireless LAN to immediately disclose the aggregation results of the data collection device In the collection system, each of the plurality of wireless terminals receives a beacon frame transmitted from the data collection device through the access point, an association request means for requesting an association from the access point, and an association response from the access point The association that remembers the association An association storage means, an aggregate host address storage means for receiving and storing the correspondence between the IP address and the MAC address of the data collection apparatus, corresponding to the unfounded ARP request from the data collection apparatus, and accessing the stored data A data transmission means for transmitting in accordance with polling from the point, and the data collection device transmits the correspondence between the IP address and the MAC address of the data collection device to the plurality of wireless terminals by broadcast without receiving response through the access point. ARP request means having no basis for storing, polling instruction means for issuing a polling operation start command to the wireless terminal registered in the polling list to the access point, and data transmitted by each of the plurality of wireless terminals through the access point, respectively Receive data A data collection result disclosing means for disclosing data collection results transmitted from the plurality of wireless terminals, and an access point. Is a beacon transmission means for transmitting beacon frames to a plurality of wireless terminals, an association response means for creating a polling list in response to an association request of the plurality of wireless terminals, and a data collection device between the plurality of wireless terminals Relay means for relaying communication, ARP request without basis from data collection device, broadcast means for broadcasting inquiry data and reception of inquiry data to a plurality of wireless terminals, and transmission of a response to the plurality of wireless terminals according to a polling list Polling means for The data collection device accesses an unrecognized ARP request means and inquiry data for transmitting and storing the correspondence between the IP address and the MAC address of the data collection device to a plurality of wireless terminals through an access point by broadcast without reception response. Inquiry data transmission means that transmits by broadcast through a point, polling operation start command means that issues a polling operation start command to a plurality of wireless terminals registered in the polling list to the access point, and response reception that receives a response through the access point Means for requesting the end of data transmission to a plurality of wireless terminals, and data summarizing result disclosing means for summing up the reception results of the response data and disclosing the summation results Good.

  This data collection system using a wireless LAN is a data collection system suitable for implementing the above-described data collection method of the present invention by the PCF method.

  With such a system, even if the number of wireless terminals increases, it is possible to avoid collisions caused by many wireless terminals transmitting response data at the same time, and the access point can receive response data from wireless terminals efficiently and quickly. it can.

  According to the present invention, the communication time between the data collection device and a large number of wireless terminals is greatly shortened, and a large amount of communication time is required when a data collection system having a large number of wireless terminals is configured using a wireless LAN system. It is now possible to eliminate major obstacles to operating the system in real time. As a result, a data collection system that operates in real time with a large number of wireless terminals that were previously considered difficult to implement using a wireless LAN can now be realized by using this data collection system. .

  Next, the details of the present invention will be described by showing embodiments of the present invention with reference to the drawings.

  FIG. 1 is a diagram showing a basic configuration in an embodiment of a data collection system of the present invention. In FIG. 1, in the data collection system 100, a data collection device 101 is coupled to an access point 103 via an Ethernet (registered trademark) 102, and the access point 103 is coupled to a wireless terminal 104 via radio. Further, a disclosure device 105 is connected to the data collection device 101. Data transmitted by the wireless terminal 104 is collected and collected by the data collection device 101 through the access point 103, and the result is immediately disclosed by the disclosure device 105.

  Here, the case where the data collection method and system using the wireless LAN of the present invention are implemented by the operation of DCF will be described first, and then the case of implementation by the operation of PCF will be described.

1) Data collection system according to DCF The present invention can basically be implemented by DCF as described in detail below.

a. System Configuration FIG. 2 is a diagram showing a configuration from the data collection device 101 to the access point 103 in the data collection system 100 of one embodiment of the present invention shown in FIG.

  In FIG. 2, a transmission / reception sequence controller 201 of the data collection apparatus 101 is connected to a keyboard 202 and a terminal operation designation command memory 203 for designating the operation of the terminal. The transmission / reception sequence controller 201 sequentially reads out the IDs of the terminals to be designated in accordance with the stored contents of the terminal operation designation command memory 203 that stores the designation order of the terminals that receive the reply transmission command, and transmits the response command signal to the designated terminals as a communication. Send to data buffer 204. This response command signal is sent from the communication data buffer 204 to the access point 103 via the Ethernet (registered trademark) 102 (local LAN). Further, the communication data buffer 204 is connected with a communication error processing retransmission device 205 and the like, and processes and retransmits the communication error. For the designation of terminals, a method of dividing the terminals into groups and sequentially designating each group and issuing a response command signal is preferably used.

  The response command signal sent to the access point data buffer 206 via the Ethernet (registered trademark) 102 is sent to the management unit 207, and this response signal is temporarily stored in the terminal management table / buffer 208. And are wirelessly transmitted from the transmission / reception unit 209 to each terminal by broadcast.

  On the other hand, response data from the wireless terminal is received by the transmission / reception unit 209 and sent to the data collection device 101 through the Ethernet (registered trademark) 102. At this time, the response data is once stored in the terminal management table / buffer 208 and collected for each group of terminals, and then sent to the data collection device 101 through the Ethernet (registered trademark) 102, whereby the transmission time of the response signal is increased. Significantly shortened.

  In the data processing apparatus 101, the response data from the wireless terminal 104 sent from the access point 103 is sent to the application unit 210 via the communication data buffer 204 and the transmission / reception sequence controller 201, and the result is disclosed. It is displayed by a display unit 211 as a device. Here, Microsoft PowerPoint is used for the application software.

  FIG. 3 is a diagram showing the configuration of the wireless terminal 104 in the data collection system 100. In FIG. 3, the transmission / reception unit 301 (with data buffer) receives a response command signal by broadcast transmission from the access point 103, and this signal is input to the sequence management unit 302 by command analysis. In the sequence management unit 302 by command analysis, this broadcast response command signal is compared with the signal of the ID designation digital SW or key input device 303, and it is determined whether or not this terminal is designated. If it is determined, the response data held by the terminal is transmitted. This response data is input by the keyboard 304, managed by the key operation management unit 305, and stored in the sequence management unit 302 by command analysis. Note that this response data is received until the transmission / reception unit 301 receives a reception response signal broadcast from the access point, and the response management unit 302 by command analysis confirms the reception response from this terminal. Retransmission is repeated by the mechanism of N (retransmission) 306. The status of these sequence management units 302 is displayed by the display unit 308 controlled by the display controller 307.

b. Communication sequence The wireless LAN normally operates with DCF. In the data collection system of the present invention based on DCF, data is exchanged by communication among the data collection device 101, the access point 103, and the wireless terminal 104 according to the communication sequence shown in FIG.

  In FIG. 4, the wireless terminal 104 that has received the beacon 401 from the access point 103 makes an association request 402 to the access point 103. The access point 103 that has received the association request registers the wireless terminal 104 in the association list and performs an association response 403 to the wireless terminal 104, thereby establishing an association between the wireless terminal 104 and the access point. .

  Next, the data collection device 101 transmits the address of the data collection device 101 through the access point 103 to the wireless terminal 104 by broadcast without reception response, and causes the wireless terminal 104 to store the address of this data collection device. (Unfounded ARP request 404). Next, the data collection apparatus 101 transmits inquiry data 405 by broadcast through the access point 103. This broadcast is repeated, for example, every 0.1 second.

  Thereafter, the data collection device 101 divides a plurality of wireless terminals registered in the access point 103 into a plurality of groups for the access point 103, and sequentially designates each group that has been grouped into the designated group. A response transmission instruction 407 command for instructing transmission of response data is sent to the wireless terminal 104 to which the access point 103 belongs, and the access point 103 responds to the command, and returns a response for each group of the plurality of divided wireless terminals 104. A transmission instruction 408 is performed. On the other hand, the response data 409 input to the wireless terminal and stored in the buffer is sequentially transmitted from each of the first set of wireless terminals 104 for which a response transmission request has been made. The data collection device 101 that has received the response data 409 collectively responds to the response reception response 410 to the wireless terminal 104 by broadcasting through the access point 103. This reply reception response 410 is repeated at regular intervals with repeated reply transmission instructions. The response data 409 from the wireless terminal at this time is given the same sequence number until a reception response is obtained, and is repeatedly transmitted, for example, every 0.5 seconds. In addition, when transmitting new response data 109 to the same inquiry, the wireless terminal 104 increases the sequence number of the response data 109 and transmits it. When the data collection device 101 receives a plurality of response data 109 from the same wireless terminal 104, only the response data with the largest scene number is processed.

  Subsequently, the data collection device 101 issues a response end instruction 411 to the access point 103. In response to this, the access point 103 ends reception of response data from each of the wireless terminals 104 in the set. Subsequently, response data is received by the same procedure as in the case of the first set of wireless terminals by the communication sequence starting from the response transmission instruction 407 to the next set of wireless terminals. When the wireless terminals are divided into three or more groups, response data is received from the wireless terminals in the same procedure for the remaining groups. In this way, the data collection apparatus 101 receives the response data for all the wireless terminals in the set, and then issues a response reception end instruction 412 to the access point 103, and the access point 103 responds to the response of the wireless terminal 104. For each of them, a response end instruction 413 is issued, and transmission / reception of response data from each wireless terminal 104 in response to transmission of inquiry data 405 from the data collection apparatus 101 is ended.

  In the above-described embodiment, a case has been described in which data collection for one wireless terminal is completed and then data for the next wireless terminal set is performed. The data collection method using the wireless LAN of the present invention can be implemented in various other forms. For example, the transmission designation time range as the transmission timing is repeatedly designated for each group, and each group of wireless data is collected. Data acquisition from terminals may be repeated, and data acquisition from each set of wireless terminals may be performed in parallel.

c. Simulation Using Network Simulator A network simulator (ns-2) was used to simulate data collection using a wireless LAN with DCF operation according to the present invention.

  As a condition for data collection, a data collection host (corresponding to a data collection apparatus including an access point in the present invention) is arranged at a point (150 m, 150 m) from the lower left in a field of 500 m × 500 m. In addition, 25 terminals are arranged in the horizontal direction every 11 m from the left corner, and are arranged in 8 rows, 16 rows, and 24 rows. Note that the wireless propagation distance between the host and the terminal is set to 250 m. Thus, direct communication can be performed between the terminal and the data collection device. Note that the wireless transmission speed for data is 11 Mbps.

Under these conditions, the following operation was performed in order to evaluate the performance when the terminal transmits data.
(1) The host transmits data to the terminal 0 5 seconds after the simulation starts. Thereby, an ARP request is transmitted from the host, and the MAC address of the host is known including other terminals.
(2) Data is transmitted from each terminal in 1 second from 10 seconds to 11 seconds after the start.
(3) There are two types of data length: 80 bytes (100 bytes including the IP header) and 480 bytes (500 bytes including the IP header).
(4) The transmission pattern is for the purpose of evaluation when access is concentrated, and the operation in which 100 terminals transmit data while shifting by 200 μs is repeated for the number of terminals per second. By doing so, the following results were obtained.

  1) First, the reception status at the host when 200 terminals transmit 80-byte data (100-byte IP packets) in a concentrated manner for every 100 terminals was examined. As a result, it was found that data from 100 terminals was transmitted in a time of about 100 ms. In this communication, 200 packets are transmitted as a whole, but 319 frames are discarded, and retransmission is performed accordingly. Since data transmission from 100 terminals is concentrated in this manner, retransmission is performed, but no data is lost due to retransmission retry out, and all data is delivered to the host in a time of about 100 ms.

  2) Next, the reception status in the host when 200 terminals transmit 480-byte data (500-byte IP packets) in a concentrated manner for every 100 terminals was examined. As a result, it was found that data from 100 terminals was transmitted in a time of about 200 ms. Further, in this communication, 392 data frames are discarded and retransmission is performed accordingly. Even when the data length is increased to this level, the number of retransmissions does not increase so much, and all the data from the terminal is delivered to the host without omission in a time of about 200 ms.

  3) Next, the reception status at the host when 400 terminals transmitted 80-byte data (100-byte IP packets) in a concentrated manner for every 100 terminals was examined. As a result, it was found that the operation of transmitting data from 100 terminals in a time of about 100 ms was repeated four times, and all data from the terminals was delivered to the host without omission.

  4) Next, the reception status in the host when 400 terminals transmit 480 bytes of data (500 bytes of IP packets) in a concentrated manner for every 100 terminals was examined. Also in this case, it was found that all data from 400 terminals were delivered to the host without omission. The number of discarded data frames is 687, and they are retransmitted.

  5) Next, the reception status in the host when the 600 terminals transmit 80-byte data (100-byte IP packets) in a concentrated manner for every 100 terminals was examined. Also in this case, it was found that all data from 600 terminals were delivered to the host without omission. The number of discarded data frames was 878, and they were retransmitted.

  6) Further, the reception status at the host when 600 terminals transmitted 480 bytes of data (500 bytes of IP packets) concentrated on every 100 terminals was examined. Also in this case, it was found that all data from 600 terminals were delivered to the host without omission. The number of data frames discarded at the MAC level is 1035, and all of them are retransmitted.

  According to the above simulation, even in a situation where 100 bytes of 500 bytes of data are concentrated and transmitted 100 times per second, all the data transmitted in the range of 1 second is distributed to the receiving host. I understood it. In this way, when a plurality of wireless terminals are grouped, for example, every 100 terminals, and data is transmitted sequentially for each grouped group, collision between signals at the time of transmission can be kept low, and communication time can be reduced. It has been found that a significant reduction can be obtained.

d. Message Format FIG. 5 shows each message format in one embodiment of the present invention. FIG. 5A shows the message format of the inquiry data. The same applies to other messages, but the first 1 byte indicates the message type. Next, the sequence number for the response data to be collected is presented. The sequence number takes 1 byte and a value up to 255. The necessary control information is as described above. The next 2 bytes are used as a reserved field, and then the body of the collected response data is prepared. This packet is transferred using UDP (User Datagram Protocol) with an emphasis on high-speed transfer, and is also transmitted as broadcast data (the destination IP address is 255.255.255.255) as described above. Since the data length can be obtained from information in the header of the IP packet, it does not need to be specified in this message.

  Next, the message format of the response data for the message is shown in FIG. The first byte is the message type. The next 1 byte indicates the sequence number of the corresponding data collection data in order to indicate which data collection the response is for. The next 2 bytes indicate the terminal identifier. Assuming a maximum number of terminals of 1000 to 2000, 2 bytes are prepared. As a result, assuming that terminal identifiers are assigned in order from 1, up to 65,535 terminals can be handled. Next, 1 byte of the sequence number of the response data is set. The response data has only a 2-bit sequence number as shown in the next reception response, and a 1-byte field is prepared here. After that is a 1-byte reserved field, followed by the response data body. In the case of this message as well as the inquiry data, a field for displaying the length is not required.

  FIG. 5C shows the message format of the reception response to the response data. As described above, the reception response to the response data is not sent individually, but the data collection device periodically broadcasts the reception response to each response data. For this reason, if it includes a pair of the identifier of the terminal that sent the response data and its response sequence number, the packet length of the reception response may increase, so prepare response fields for all terminals in advance. The terminal identifier is indicated by its relative position. As the response field, 2 bits are prepared for each terminal, and three response sequences, 1, 2, and 3, are used in order.

  In FIG. 5C, the first byte is a message type. From the next time, the response sequence numbers from terminal 1 to 2044 are consecutive. As described above, each sequence number is represented by 2 bits, and includes 0 when no response data is received from the terminal, and the last received sequence number when it is received. As a result, the data collection apparatus can know from which wireless terminal up to which response sequence number is received. Since the reception sequence number is 1 to 3, each terminal can return only two response data at maximum without a reception response. That is, if three response data are input consecutively before a periodic reception response comes in response to the same inquiry, the last one cannot be transmitted. However, if a periodic reception response is transmitted once every 0.1 seconds, the response data arriving at the data collection device is a number of 0.1 seconds even if the reception-response may be lost. Responded within double time. Since this is a sufficiently short time compared with the operation of the responder who inputs the response to the terminal, 2 bits is sufficient as the response sequence number, for example.

2) PCF based data collection system a. Configuration of Data Collection System FIG. 6 is a diagram showing an embodiment of a configuration of a response data collection system using a wireless LAN according to the present invention. In FIG. 6, a response data collection system 1 using a wireless LAN is composed of a data collection device 101, an access point 103, and a wireless terminal 104. The access point 103 is a centralized station that performs a polling operation in the PCF. Playing a role.

  The data collection apparatus 101 has no ARP request means 6101 for sending the address of the data collection apparatus to the wireless terminal 104 by broadcast without reception response, inquiry data transmission means 6102 for sending inquiry data by broadcast, access point 103, a response command unit 6103 for issuing a polling operation start command, a response reception unit 6104 for receiving a response from the wireless terminal, a response reception response unit 6105 for collectively transmitting the response reception responses, and the wireless terminal 104 On the other hand, a response end requesting unit 6106 for instructing the end of transmission of response data and a totaling result disclosing unit 6107 for totaling the reception results of the response data and disclosing the totaling result are provided.

  The access point 103 includes a beacon transmission unit 6201 that transmits a beacon frame to the wireless terminal 104, an association response unit 6202 that creates a polling list in response to an association request from the wireless terminal 104, and between the data collection device 101 and the wireless terminal 104. Polling for performing a polling operation in response to a polling operation command by a relay means 6203 for relaying communication, broadcast means 6204 for broadcasting transmission from the data collection apparatus 101 to the wireless terminal 104, and response instruction means 6103 issued by the data collection apparatus 101 Means 6205 are provided.

  Further, the wireless terminal 104 receives a beacon frame transmitted from the access point 103, a beacon receiving unit 6301, an association request unit 6302 that requests an association from the access point 103, and an association storage that stores an association by an association response from the access point 103. Means 6303, total host address storage means 6304 for storing the correspondence between the IP address and MAC address of the data collection device in response to an unfounded ARP request from the data collection device 101, and inquiry data from the data collection device 101 Inquiry data receiving means 6305 for receiving and response data transmitting means 6306 for receiving response data in response to polling from the access point 103 are provided.

  In the response data collection system 1 using the wireless LAN, a plurality of wireless terminals 104, for example, 500 or more can be provided for one access point 103 and operated as a real-time response data collection system. As will be described later, 1000 or 2000 wireless terminals 104 can be provided and operated as a real-time response data collection system.

In the response data collection system 1 using the wireless LAN, the data collection device 101 and the access point 103 are connected by Ethernet (registered trademark). A plurality of access points 103 can be provided for one data collection apparatus 101. In this case, mutual interference can be avoided by using a plurality of different access points.
b. Communication sequence of response data collection system

  FIG. 7 shows a communication sequence of the response data collection system using the wireless LAN based on the PCF shown in FIG. In FIG. 7, the wireless terminal 104 that has received the beacon 701 from the access point 103 makes an association request 702 to the access point 103. The access point 103 that has received this association request registers this wireless terminal 104 in the polling list, and establishes an association between this wireless terminal 104 and this access point by making an association response 703 to this wireless terminal 104. To do.

  Next, the data collection apparatus 101 makes an unfounded ARP request 704. In other words, the address of the data collection device 101 is transmitted to the wireless terminal 104 through the access point 103 by broadcast without reception response, and the wireless terminal 104 stores the address of the data collection device 101. Next, the data collection apparatus 101 transmits inquiry data 705 by broadcast through the access point 103. This broadcast is repeated, for example, every 0.1 second.

  Thereafter, the data collection device 101 sends a response start request 706 command that instructs the access point 103 to perform polling for response data transmission to the wireless terminal registered in the access point 103 polling list. The access point 103 makes a reply transmission request 708 by sequentially polling each of the wireless terminals 104. On the other hand, response data 709 input by the response data input person and stored in the buffer is sequentially transmitted from each of the wireless terminals 104. The data collection device 101 that has received the response data 709 collectively responds to the reception response 710 to the wireless terminal 104 by broadcast through the access point 103. The response data is given the same sequence number until a reception response is obtained, and is repeatedly transmitted, for example, every 0.5 seconds. In response to the same inquiry, the wireless terminal 104 increases the sequence number of the response data when transmitting new response data. When receiving a plurality of response data from the same wireless terminal 104, the data collection device 101 processes only the response data having the largest scene number.

  Thereafter, the data collection device 101 issues a response end instruction 711 to the access point 103. The access point 103 responds with a response end response 712 and ends polling for each of the wireless terminals 104. As a result, the transmission of the response data 709 from each of the wireless terminals 104 ends.

  The data collection apparatus 101 totals the reception results of the response data 709 immediately after the completion, and performs a total result disclosure 713 in real time.

3) Configuration of Data Collection System Network Using Wireless LAN FIG. 8 is a diagram showing a network configuration in an embodiment of a response data collection system of the present invention using four wireless LAN interface devices as access points. .

  In the data collection 80 shown in FIG. 8, in addition to the main personal computer (PC) 82 as an inquiry aggregation host, a line monitoring individual ID display PC 83 is connected to the Ethernet (registered trademark) 81, and a server PC 84 is further connected. , Have adjusted the operation of the system. The Ethernet (registered trademark) 81 is connected to four wireless LAN interface devices 85, 86, 87 and 88 as access points, and can be coupled to a plurality of wireless terminals 851, 861, 871 and 881 by radio. It is arranged to be. In this configuration, the four wireless LAN interface devices can be operated with different transmission / reception times, thereby preventing mutual interference. Further, as these four wireless LAN interface devices, by using devices having different frequency bands, the number of wireless terminals that can be handled by one wireless LAN interface device can be increased, and a large-scale data collection system can be used. It turns out that it can be configured.

  The data collection system 80 can execute communication in the following order. First, the host PC of the data collection system 80 is set to the maintenance screen and it is confirmed that communication is possible. Next, a connection test command is transmitted instead of an unfounded ARP request. The wireless terminals 851 to 881 collate the MAC address with the ID number, store (store) the data, and transmit the MAC address and the ID number. This connection test is repeated until all terminal IDs can be connected.

  When the connection test is completed, an inquiry request from the host PC 82 is sequentially transferred to each wireless LAN interface 85 to 88 via the server PC 83 and transmitted to each wireless terminal 851 to 881, and response data from each wireless terminal 851 to 881 is The response data transmission from each wireless LAN interface 85-88 is adjusted by the server PC 83 and sequentially sent to the host PC 82 together with the individual ID.

  When a termination command is issued from the host PC 82 based on the monitoring result of the individual ID, this is transmitted to the server PC 84, each of the wireless LAN interfaces 85 to 88, and the wireless terminals 851 to 881, and the transmission of the response data is completed.

  According to the present invention, the communication time between the data collection device and a large number of wireless terminals can be greatly shortened. When a response data collection system having a large number of wireless terminals is conventionally configured using a wireless LAN system, the communication time is large. The solution to the problem of hindering real-time operation, which required a long communication time, was obtained. As a result, by using the present invention, it is possible to realize a response data collection system that uses wireless LAN, which has been considered difficult in the past, and receives and counts responses from a large number of wireless terminals and discloses the count results in real time. Became. For this reason, the industrial applicability of the present invention is great.

It is a figure which shows the structure of the data collection system in one Embodiment of this invention. It is the figure which showed the structure from the data collection apparatus in one Embodiment of the data collection system using wireless LAN of this invention to an access point. It is the figure which showed the structure of the wireless terminal in one Embodiment of the data collection system using wireless LAN of this invention. It is a figure which shows the communication sequence of the data collection system in one Embodiment of the data collection system using wireless LAN of this invention. In one embodiment of a data collection system using a wireless LAN of the present invention, (a) a message format of inquiry data, (b) a message format of response data to the inquiry message, and (c) a message format of reception response of the response data. FIG. It is the figure which showed the structure of the apparatus in one Embodiment of the data collection system using wireless LAN of this invention. It is a figure which shows the communication sequence of the data collection system in one Embodiment of the data collection system using wireless LAN of this invention. It is the figure which showed the network structure in one Embodiment of the data collection system of this invention using four wireless LAN interface apparatuses.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Reply data collection system, 101 ... Data collection device, 102 ... Ethernet (registered trademark), 103 ... Access point, 104 ... Wireless terminal, 201 ... Transmission / reception sequence controller, 202 ... Keyboard, 203 ... Terminal operation designation command memory, 204 ... Communication data buffer, 205 ... Communication error processing retransmission, etc., 206 ... Access point data buffer, 207 ... Management unit, 208 ... Terminal management table / buffer, 209 ... Transmission / reception unit, 210 ... Application unit, 211 ... Display unit, 301 ... Transmission / reception unit 302 ... Sequence management unit by command analysis 303 ... ID designation digital SW or key input device 304 ... Keyboard, 305 ... Key operation management unit 306 ... Response signal response Y / N (retransmission) 307 ... Display controller, 308 ... Display unit, 401 ... Beacon, 402 ... Association request, 403 ... Association response, 404 ... Unfounded ARP request, 405 ... Inquiry data, 406 ... Inquiry data (retransmission), 407 ... Response start instruction 408 ... Reply transmission instruction, 409 ... Reply data, 410 ... Reply reception response, 411 ... Reply transmission end instruction, 412 ... Reply reception end instruction, 213 ... Reply transmission end instruction, 6101 ... Unfounded ARP request means, 6102 ... Inquiry data transmission means 6103 ... Response command means 6104 ... Response reception means 6105 ... Response reception response means 6106 ... Response end request means 6107 ... Total result disclosure means 6201 ... Beacon transmission means 6202 ... Association response means, 6203 ... Middle joint 6204: Polling means, 6301 ... Beacon receiving means, 6302 ... Association request means, 6303 ... Association confirmation means, 6304 ... Total host address storage means, 6305 ... Inquiry data receiving means, 6306 ... Response data sending means, 701 ... Beacon, 702 ... Association request, 703 ... Association response, 704 ... Unfounded ARP request, 705 inquiry data, 706 ... Response start request, 707 ... Response start response, 708 ... Response transmission request, 709 ... Response data, 710 ... Reception response, 711 ... Response end request, 712 ... Response end response, 713 ... Total result disclosure, 80 ... Data collection system, 81 ... Ethernet (registered trademark), 82 ... Personal computer (PC), 83 ... Line monitoring individual ID display PC, 4 ... server PC, 85,86,87,88 ... wireless LAN interface device (access point), 851-85n, 861-86n, 871-87n, 881-88n ... wireless terminal.

Claims (11)

A plurality of wireless terminals that transmit data; an access point that is wirelessly connected to the plurality of wireless terminals and that receives data transmitted from the plurality of wireless terminals; and is transmitted from the plurality of wireless terminals and acquired by the access point A data collection method using a wireless LAN that collects data transmitted from the plurality of wireless terminals by the data collection device.
A communication channel is established by transmitting a signal for establishing a communication channel from the access point to the plurality of wireless terminals, and an IP address of the data collection device is transmitted from the access point to the plurality of wireless terminals. And the MAC address correspondence information, a specific wireless terminal is designated from the plurality of wireless terminals to the plurality of wireless terminals from the access point, and a data transmission instruction is broadcast to the specific wireless terminal Then, each of the plurality of wireless terminals responds to the data transmission instruction transmitted from the access point by the broadcast, determines whether or not it is specified, and if it is determined that the data is specified, A data collection method using a wireless LAN, characterized by transmitting.   2. The wireless LAN according to claim 1, wherein the specific wireless terminal designation from the access point and the broadcast transmission for a data transmission instruction to the designated specific wireless terminal are repeatedly performed at predetermined time intervals. Data collection method using   The wireless LAN according to claim 1, wherein the data transmission instruction from the access point to the specific wireless terminal includes a transmission timing specification that specifies a transmission time range of the data from the specific wireless terminal. Data collection method used.   4. The wireless LAN according to claim 3, wherein the specified specific wireless terminal transmits data asynchronously with the other specified specific wireless terminal within the transmission time range and at the same time. Data collection method using   Identification information for individually identifying the plurality of wireless terminals is assigned to each of the plurality of wireless terminals, and the plurality of wireless terminals are individually identified in a response signal transmitted from the data collection device. The data collection method using a wireless LAN according to claim 1, wherein identification information to be included is included.   3. The response signal for notifying that data has been received after a lapse of a predetermined time from reception of data from the specific wireless terminal is broadcast from the access point. A data collection method using the described wireless LAN.   The response signal transmitted from the access point includes a field made up of predetermined bits for individually specifying the plurality of wireless terminals, and each of the plurality of wireless terminals individually corresponds to the bit position of the field. The data collection method using a wireless LAN according to claim 6, wherein   Response signals for reception of data transmitted from each of the plurality of wireless terminals are collected from the access point and broadcast at regular intervals, and each of the plurality of wireless terminals broadcasts from the access point. 7. The data collection using a wireless LAN according to claim 6, wherein when the response signal for receiving the transmitted data does not include a response signal for the transmitted data, the data is retransmitted. Method. A plurality of wireless terminals that transmit data; an access point that is wirelessly connected to the plurality of wireless terminals and that receives data transmitted from the plurality of wireless terminals; and that the plurality of wireless terminals transmit and receive by the access point A data collection method for collecting data transmitted from the plurality of wireless terminals by the data collection device using a data collection device for collecting data,
A signal for establishing a communication channel is transmitted from the access point to the plurality of wireless terminals to establish a communication channel, and the access point indicates an operating state of the plurality of wireless terminals after the communication channel is established. Information is acquired, and correspondence information between the IP address and the MAC address of the data collection device is transmitted from the access point to the plurality of wireless terminals, and the access point is based on a data transmission instruction from the data collection device. In response to the data transmission instruction from the access point, the wireless terminal transmits the data to the predetermined wireless terminal corresponding to the information indicating the operating state in the plurality of wireless terminals. A data collection method using a wireless LAN. A plurality of wireless terminals, an access point that is wirelessly connected to the plurality of wireless terminals, receives data transmitted from the plurality of wireless terminals, and collects data from the plurality of wireless terminals received at the access point And a data collection system using a wireless LAN that immediately discloses the aggregation result of the data collection device, the data collection device comprising a data collection device for aggregation and a disclosure device for disclosing the aggregation result of the data collection device,
Each of the plurality of wireless terminals includes:
Communication channel establishment means for establishing a communication channel by receiving a signal for establishing a communication channel issued by the access point to the plurality of wireless terminals;
Address correspondence receiving means for receiving correspondence information between an IP address and a MAC address of the data collection device issued by the access point to the plurality of wireless terminals;
The plurality of wireless terminals are grouped into a plurality of groups, each group is sequentially designated, and broadcast transmission from the access point that instructs data transmission to the wireless terminals belonging to the designated group is received. Response determination means for determining whether or not to respond in response to the data transmission instruction transmitted by the broadcast;
Response transmission means for transmitting data to be transmitted when it is determined that a response should be made,
The access point is
Communication channel establishment means for establishing a communication channel by transmitting a signal for establishing a communication channel to the plurality of wireless terminals;
Address corresponding transmission means for transmitting correspondence information between the IP address and MAC address of the data collection device to the plurality of wireless terminals;
In accordance with a command from the data collection device, the plurality of wireless terminals are grouped into a plurality of groups, each group is sequentially designated, and a data transmission instruction to the wireless terminals belonging to the designated group is broadcast. A data transmission instruction broadcast means for transmitting,
The data collection device includes:
The plurality of wireless terminals are grouped into a plurality of groups, each group is sequentially designated, and an instruction to transmit data to the wireless terminals belonging to the designated group is broadcasted to the access point A data collection system using a wireless LAN, comprising data transmission instruction broadcast instruction means. A plurality of wireless terminals, an access point that is wirelessly connected to the plurality of wireless terminals and receives data transmitted from the plurality of wireless terminals, and data transmitted from the plurality of wireless terminals acquired by the access point A data collection system using a wireless LAN that includes a data collection device that collects and aggregates, and a disclosure device that discloses the aggregation results of the data collection device, and that aggregates the data collection devices and immediately discloses the aggregation results,
Each of the plurality of wireless terminals includes:
Beacon receiving means for receiving a beacon frame transmitted from the data collection device through the access point;
Association request means for requesting association to the access point;
Association storage means for storing an association by an association response from the access point;
In response to an unfounded ARP request from the data collection device, aggregate host address storage means for receiving and storing the correspondence between the IP address and MAC address of the data collection device;
Data transmission means for transmitting stored data according to polling from the access point,
The data collection device includes:
An unreasonable ARP request means for transmitting and storing the correspondence between the IP address and the MAC address of the data collection device through the access point through the access point by broadcast without reception response;
Polling command means for issuing a command to start polling operation for the wireless terminal registered in the polling list for the access point;
Data receiving means for receiving data transmitted by each of the plurality of wireless terminals through the access point;
A response end request means for instructing the end of data transmission to the plurality of wireless terminals;
Data collection result disclosing means for disclosing data collection results transmitted by the plurality of wireless terminals,
The access point is
Beacon transmitting means for transmitting beacon frames to the plurality of wireless terminals;
An association response means for creating a polling list in response to an association request of the plurality of wireless terminals;
Relay means for relaying communication between the data collection device and the plurality of wireless terminals;
Broadcast means for broadcasting the ARP request, inquiry data, and inquiry data reception from the data collection device to the plurality of wireless terminals;
Polling means for requesting transmission of responses to the plurality of wireless terminals according to the polling list,
The data collection device includes:
ARP request means having no basis for transmitting and storing the correspondence between the IP address and the MAC address of the data collection device by broadcast without reception response through the access point to the plurality of wireless terminals;
Inquiry data transmission means for transmitting inquiry data by broadcast through the access point;
Polling operation start command means for issuing a polling operation start command to a plurality of wireless terminals registered in the polling list for the access point;
A response receiving means for receiving a response through the access point;
A response end request means for instructing the end of data transmission to the plurality of wireless terminals;
A data collection system using a wireless LAN, comprising: data summarization result disclosing means for summing up reception results of response data and disclosing the summation results.

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